Wireless communication systems are well known in the art, such as the 3rd Generation (3G) of mobile telephone standards and technology. An example of such 3G standards and technology is the Universal Mobile Telecommunications System (UMTS), developed by the 3rd Generation Partnership Project (3GPP) (www.3gpp.org).
Typically, wireless communication units, or User Equipment (UE) as they are often referred to, communicate with a Core Network (CN) of a wireless communication system via a Radio Network Subsystem (RNS). A wireless communication network typically comprises a plurality of radio network subsystems, each radio network subsystem comprising one or more cells to which UEs may attach, and thereby connect to the network.
Access to a network, or services provided by the network, is typically authorised by the CN of the network. Furthermore, such access to the network is typically provided irrespective of the particular cell to which a UE is attached, so long as they are within communication range of a serving base station. However, the inventor has recognised that in certain circumstances it may be desirable for access to the network via specific cells to be limited, for example to specific UEs or users, or indeed access to be prevented for specific UEs or users.
By way of example, femto-cell or pico-cell Access Points (APs) are a recent development within the field of wireless cellular communication systems. Femto-cells or pico-cells are effectively communication coverage areas supported by low power base stations (otherwise referred to as serving communication units). These cells are able to be piggy-backed onto the more widely used macro-cellular network and support communications to UEs in a restricted, for example ‘in-building’, environment. Typical applications for such femto-cell or pico-cell APs include, by way of example, residential and commercial (e.g. office) locations, ‘hotspots’, etc, whereby an AP can be connected to a core network via, for example, the Internet using a broadband connection or the like. In this manner, femto-cells or pico-cells can be provided in a simple, scalable deployment in specific in-building locations where, for example, network congestion at the macro-cell level is an issue.
As will be appreciated, where the provider of the AP is a homeowner, business, etc., for example in a case of residential or commercial applications, public access to the network via the AP would be undesirable. Accordingly, it would be desirable for access to the network via such APs to be limited, for example to specific UEs or users, or access to be prevented for specific UEs or users.
As previously mentioned, access to a network, or services provided by the network, is typically authorised by the CN. When a UE moves from one location area to another location area, the UE sends a location update request to the core network, the location update request typically comprises a mobile subscriber identity number for the UE and a location area code (LAC) for the location area for which the UE has moved into. In order for the CN to limit access for individual cells, it would be necessary for each cell to be provided with a unique LAC. As will be appreciated by a skilled artisan, the LAC typically only comprises 16 bits, and as such only 65,535 unique LACs are possible. Since wireless communication networks typically comprise individual cells which number in the millions, using the LAC to limit access for individual cells is clearly not a practical solution.
3GPP technical specification 22.043 defines Support of Localized Service Area (SoLSA), which specifies a mechanism that can be used as a platform for providing special tariffs, and/or a special set of service features for certain subscriber units within a regionally restricted area or areas. In particular, SoLSA allows a network operator to offer subscribers, or groups of subscribers, different services, different tariffs and different access rights depending on their geographical location.
A problem with SoLSA is that it requires the CN, the radio network sub-system (RNS) and the UE to be upgraded in order to support this functionality. This is a particular problem with regard to UEs, since it takes significant effort and a long time for new functionality to be provided within UEs, and to achieve a level of market penetration where it becomes possible to rely on the use of the new functionality. As a consequence, there has been limited, if any, support for SoLSA. Thus, SoLSA has failed to provide a suitable mechanism with which to limit access to the network for individual cells.
Thus, there exists a need for a method and apparatus for providing access control for a cellular communication network, which aims to address at least some of the shortcomings of past and present access control techniques and/or mechanisms.